As the sophistication level of communications technology increases, the options for communications service have become more varied. For example, in the last 30 years in the telecommunications industry, personal communications have evolved from a home having a single rotary dial telephone, to a home having multiple telephone, cable and/or fiber optic lines that accommodate both voice and data. Additionally, cellular phones and Wi-Fi have added a mobile element to communications. Similarly, in the entertainment industry, 30 years ago there was only one format for television and this format was transmitted over the air and received via antennas located at homes. This has evolved into both different standards of picture quality such as, standard definition TV (SDTV), enhanced definition TV (EDTV) and high definition TV (HDTV), and more systems for delivery of these different television display formats such as cable and satellite. Additionally, services have grown to become overlapping between these two industries. As these systems continue to evolve in both industries, the service offerings will continue to merge and new services can be expected to be available for a consumer. Also these services will be based on the technical capability to process and output more information, for example as seen in the improvements in the picture quality of programs viewed on televisions, and therefore it is expected that service delivery requirements will continue to rely on more bandwidth being available throughout the network including the “last mile” to the end user.
Another related technology that impacts both the communications and entertainment industries is the Internet. The physical structures of the Internet and associated communication streams have also evolved to handle an increased flow of data. Servers have more memory than ever before, communications links exist that have a higher bandwidth than in the past, processors are faster and more capable and protocols exist to take advantage of these elements. As consumers' usage of the Internet grows, service companies have turned to the Internet (and other Internet Protocol (IP) networks) as a mechanism for providing traditional services. These multimedia services include IP television (IPTV, referring to systems or services that deliver television programs over a network using IP data packets), video on demand (VOD), voice over IP (VoIP), and other web related services received singly or bundled together.
To accommodate the new and different ways in which IP networks are being used to provide various services, new network architectures are being developed and standardized. Internet Multimedia Subsystem (IMS) is an architectural framework utilized for delivering IP multimedia services to an end user. The IMS architecture has evolved into a service-independent topology which uses IP protocols, e.g., Session Initiation Protocol (SIP) signaling, to provide a convergence mechanism for disparate systems. More specifically, the SIP protocol was designed as a signaling protocol for establishing application sessions and the IMS architecture relies on the SIP protocol and defines security mechanisms and protocols that protect the signaling.
In the Open Mobile Alliance (OMA) forum, the generic term “SIP/IP core” is often used to refer to a SIP-based architecture that can be also based on IMS or any other architecture with similar properties. In a system employing a SIP/IP core, SIP messages are usually routed through a series of proxies before reaching their destinations. SIP signaling in general crosses operator boundary domains, e.g. when a user is roaming or when the sender and the receiver belong to different security domains. Signaling protection in such situations is achieved hop-by-hop using security measures varying from cryptography, VPN to physical isolation and dedicated lines. For example, RFC 3261 specifies several security mechanisms for protecting SIP signaling. These mechanisms include digest authentication, which allows SIP entities to authenticate each other and prevents replay attacks, but does not deal with confidentiality. Another mechanism referred to in RFC 3262 called TLS provides only hop-by-hop security for signaling.
Traditionally, the media path associated with a connection handled by a SIP/IP core based system (which is sometimes also called the “application path” or “user data path”) is separated from the signaling path (which is sometimes also called the “control path”) associated with that same connection. Whereas SIP is used for the signaling path, other protocols are typically used for the media path such as RTP, HTTP or MSRP. The security mechanisms for protecting the media path can vary based on the sensitivity of the data, business models, operator policies and regulation. In general, the protection requirements for SIP signaling will differ from the ones for media/data path protection due to different type of information carried in each case.
Some application servers and enablers have started to use SIP for transporting application/user data as additional payloads. For example, short messaging, location, presence, personal data and device management services have begun to use SIP to carry payloads. Some of these applications may carry data that is not sensitive and thus the underlying SIP/IP core security is sufficient for them. More specifically, in IMS networks,
SIP messages are protected by IPSec along the communication path from terminal to P-CSCF and vice versa and the IMS core (i.e., the portion of the network where the P/I/S-CSCF, the HSS, and various IMS application servers are located) is assumed to be secure, by IP Domain Security or physical means. In typical SIP networks, hop-by-hop message authentication or TLS is often used, however, S/MIME is also being considered for protecting separate elements of SIP messages.
There are, however, applications that use SIP payloads to transport end-to-end sensitive data for which the underlying SIP/IP core security described above is not sufficient. User data that is carried in SIP payloads will be visible to SIP proxies if no end-to-end encryption is applied. This is likely to be unacceptable for applications where user privacy is a big concern. For example, information about a user's current location should not be disclosed to parties other than those authorized by the user. Similarly, presence information, address book information, and the like could be sensitive from user's privacy perspective.
Accordingly, it would be desirable to provide systems and methods which address security issues in such architectures and, more specifically, which protect application data SIP payloads with additional security mechanisms that meet the end-to-end security requirements.